Staging Submersion Heaters to operate on/off like an Hvac system


#1

I currently have my heaters designed to turn on and off based on a certain temp (the low and high setpoints of that temp). But I need them to actually regulate the temp and turn on and off as needed like an Hvac system does when it is set on auto.

I guess I need help getting my submersion heaters to be more on an auto mode rather than the manual mode I kind of have them on if that makes sense. I am not sure how to write that into my strategy at all but I am also not sure if the equipment is my issue in some way too. How do I know if the heaters we have are capable of this and what type of module should I switch too? If I currently have them on d.o. modules for on/off only do I need to switch them to an a.o. to be able to ramp them up and down for more of an auto mode?

I am completely new to all of this and this is the very first strategy I have worked with.


#2

Welcome to the Forums.

Couple of quick thoughts / questions…

  1. What is prompting this change? Sounds like the temperature is varying too much?
    What if you just moved the on and off set point closer together? There would be less variation and zero change required to the strategy? (I’m sure you have thought of this, I am just trying to understand the process and the reasoning behind changing it).

  2. You say that you have set points for on and off, but then you also mention that they are in manual mode and you want an auto mode. I am a little confused if they are being controlled by an Opto system or some other computer system now?

  3. Can you please describe the equipment a little more? You mention that you have digital out module at the moment for the on off control, but it sounds like there is an analog option? This would only be possible if the equipment supports it. Note that usually heating elements only have on/off control as full analog control of heating elements is really expensive. (It takes a lot of power to control the power flowing into a heating element).

  4. Can you outline what sort of Opto gear you have? Is it a SNAP PAC System? Ultimate? Mystic? Factory Floor?


#3

Hello Beno and thank you for replying! I thought it would be easier if I just copied your questions and answered them. Thank you again for your help and I really appreciated your input. I am completely new to this and looking to learn anything I can.

  1. What is prompting this change? Sounds like the temperature is varying too much? Temp is varying too much and also contactors are wearing out too quickly and having to be replaced.
    What if you just moved the on and off set point closer together? This could work, right now we are keeping them 5 degrees apart, do you suggest less than that? There would be less variation and zero change required to the strategy? (I’m sure you have thought of this, I am just trying to understand the process and the reasoning behind changing it). They may have tried this in the past, I will ask and find out.
  2. You say that you have set points for on and off, but then you also mention that they are in manual mode and you want an auto mode. I am a little confused if they are being controlled by an Opto system or some other computer system now? They were originally in just an A.I. mode where we were getting temp readings but we actually had to walk up to a breaker to turn them on/off. Now they are on a digital output mode and we can turn them on and off based on the setpoints but I have been asked to stage them like an Hvac unit to maintain temp so that temp is no longer varying and also to stop the contactors from wearing out so quickly which will become very costly over time.
  3. Can you please describe the equipment a little more? You mention that you have digital out module at the moment for the on off control, but it sounds like there is an analog option? This would only be possible if the equipment supports it. Note that usually heating elements only have on/off control as full analog control of heating elements is really expensive. (It takes a lot of power to control the power flowing into a heating element). I am controlling the heaters through a D.O. snap-OAC5MA and I am getting the A.I. reading for the temp from a snap-AITM8.
  4. Can you outline what sort of Opto gear you have? Is it a SNAP PAC System? Ultimate? Mystic? Factory Floor? I am working with a snap-pac rack using a R1 and an EB1.
    Thank you– Ashley

#4

What is the power output on your heaters? Could you add a solid state relay?

( What I am thinking: SSR -> TPO -> PID -> FTW :wink: )


#5

Some thoughts that echo exactly what Philip recommends;
From the questions;

  1. For sure sounds like the contactors are the prime or core issue.
    Take a look at replacing the contactors with SSR’s.

  2. The temperature is not as finely controlled as it can be because of concern about contactor life span.
    Replace the contactors with SSR’s. No moving parts to wear out. Correctly rated wiring and heat-sinking will ensure that the SSRs will lasts for many many years.

  3. The SNAP-OAC5MA is compatible with most of the SSR’s that you would probably end up replacing the contactors with.

  4. The R1 and EB1 will control the SSR’s just fine - there should be no control strategy changes required in replacing the existing contactors with SSR’s.


#6

Thank you for the help :+1:t3::+1:t3::+1:t3: